Vertical permeability and sediment consolidation measurements were taken on seven whole-round drill cores from Sites 1253 (three samples), 1254 (one sample), and 1255 (three samples) drilled during Ocean Drilling Program Leg 205 in the Middle America Trench off of Costa Rica's Pacific Coast. Consolidation behavior including slopes of elastic rebound and virgin compression curves (Cc) was measured by constant rate of strain tests. Permeabilities were determined from flow-through experiments during stepped-load tests and by using coefficient of consolidation (Cv) values continuously while loading. Consolidation curves and the Casagrande method were used to determine maximum preconsolidation stress. Elastic slopes of consolidation curves ranged from 0.097 to 0.158 in pelagic sediments and 0.0075 to 0.018 in hemipelagic sediments. Cc values ranged from 1.225 to 1.427 for pelagic carbonates and 0.504 to 0.826 for hemipelagic clay-rich sediments. In samples consolidated to an axial stress of ~20 MPa, permeabilities determined by flow-through experiments ranged from a low value of 7.66 x 10–20 m2 in hemipelagic sediments to a maximum value of 1.03 x 10–16 m2 in pelagic sediments. Permeabilities calculated from Cv values in the hemipelagic sediments ranged from 4.81 x 10–16 to 7.66 x 10–20 m2 for porosities 49.9%–26.1%.
1McKiernan, A.W., and Saffer, D.M., 2006. Data report: Permeability and consolidation properties of subducting sediments off Costa Rica, ODP Leg 205. In Morris, J.D., Villinger, H.W., and Klaus, A. (Eds.), Proc. ODP, Sci. Results, 205 [Online]. Available from World Wide Web: <http://www-odp.tamu.edu/publications/205_SR/203/203.htm>. [Cited YYYY-MM-DD]
2Pennsylvania State University, 320 Deike Building, University Park PA 16802, USA. Correspondence author: amckiern@geosc.psu.edu
Initial receipt: 22 June 2004
Acceptance: 24 May 2005
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publication: 20 January 2006
Ms 205SR-203